• Journal of Mechanical Science and Technology
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• 제18권2호
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• pp.211-220
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• 2004

It is well known that the geometry of the articular surface has a major role in determining the position of articular contact and the lines of action for the contact forces. The contact force calculation of the knee joint under the effect of sliding and rolling is one of the most challenging issues in this field. We present a 3-D human knee joint model including sliding and rolling motions and major ligaments to calculate the lateral and medial condyle contact forces from the recovered total internal reaction force using inverse dynamic contact modeling and the Least-Square method. As results, it is believed that the patella, muscles and tendon affect a lot for the internal reaction forces at the initial heel contact stage. With increasing flexion angles during gait, the decreasing contact area is progressively shifted to the posterior direction on the tibia plateau. In addition, the medial side contact force is larger than the lateral side contact force in the knee joint during normal human walking. The total internal forces of the knee joint are reasonable compared to previous studies.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.25.1-25
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• 2001

Intelligent Space is a space where many sensors and intelligent devices are distributed. Mobile robots exist in this space as physical agents, which provide human with services. To realize this, human and mobile robots have to approach each other as much as possible. Moreover, it is necessary for them to perform interactions naturally. Thus, it is desirable for a mobile robot to carry out human-affnitive movement. In this research, a mobile robot is controlled by the Intelligent Space through its resources. The mobile robot is controlled to follow walking human as stably and precisely as possible.

• 한국지능시스템학회논문지
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• 제21권3호
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• pp.353-358
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• 2011

본 논문에서는 이족 로봇을 위한 가상의 다리에 기반한 보행 모델을 제시한 후, 시뮬레이션을 통하여 제시한 보행 모델의 근본적인 롤/피치/요(roll/pitch/yaw) 운동 특성을 분석한다. 이를 위하여 로봇의 무게 중심과 압력 중심에서의 운동 경로를 사람의 발걸음 운동 패턴과 유사한 임의의 패턴으로 설정하고, 이러한 경로를 따라 보행할 경우에 나타나는 주요 관성 성분 특성을 확인한다. 결과적으로, 이족 보행에서 롤, 피치 및 요 방향으로의 운동은 보행과정에서 생성될 수 있는 자연스러운 현상이며, 이것은 발걸음의 간격, 무게 중심의 위치 및 로봇 몸체의 이동가속도와 밀접한 관계가 있음을 보인다. 또한, 이족보행의 밸런스 관점에서 발의 위치 설정을 위한 경로계획의 중요성을 고찰한다.

• Physical Therapy Rehabilitation Science
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• 제13권2호
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• pp.152-162
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• 2024

Objective: This study was conducted to analyze the effect of wearable Electromyography-controlled functional electrical stimulation (EMG-controlled FES) System on Gait Function and cardiopulmonary metabolic efficiency during walking in older adults. Design: Cross-section study Methods: Total 22 older adult participants suitable to selection criteria of this study participated in this study. The EMG-controlled FES System, which functions as a wearable physical activity assist FES system was used. All participations performed randomly assigned two conditions (Non-FES assist [NFA], FES assist [FA]) of walking. In all conditions, spatio-temporal parameters and kinematics and kinetics parameters during walking was collected via 3D motion capture system and 6 minutes walking test (6MWT) and metabolic cost during walking and stairs climbing was collected via a portable metabolic device (COSMED K5, COSMED Srl, Roma, Italy). Results: In Spatio-temporal parameters aspects, The EMG-controlled FES system significantly improved gait functions measurements of older adults with sarcopenia at walking in comparison to the NFA condition (P<0.05). Hip, knee and ankle joint range of motion increased at walking in FA condition compared to the NFA condition (P<0.05). In the FA condition, moment and ground reaction force was changed like normal gait during walking of older adults in comparison to the NFA condition (P<0.05). The EMG-controlled FES system significantly reduced net cardiopulmonary metabolic energy cost, net energy expenditure measurement at stairs climbing (P<0.05). Conclusions: This study demonstrated that EMG-controlled FES is a potentially useful gait-assist system for improving gait function by making joint range of motion and moment properly.

• 한국정밀공학회지
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• 제19권10호
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• pp.139-146
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• 2002

We developed a motion capture system to utilize informations on the human walking motion. The system is composed of the mechanical and electronic devices to obtain the joint angle data and the software to analyze the obtained data and to transform the data into the input for a biped walking robot. The mechanical system is composed of a pair of links with 3 revolute joints, on which potentiometers are attached on joint axes to sense rotation angles. Analog signals from potentiometers are transformed into the digital data through the low pass filter and the A/D converter, and then which are stored at the computer. We analyzed the walking characteristics by applying FFT to the digital data, and then performed a 3-D computer simulation using the data. Finally, We apply the processed data to a biped walking robot.

• 제어로봇시스템학회논문지
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• 제17권10호
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• pp.1029-1036
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• 2011

An energy-efficient reference walking trajectory generation algorithm is suggested utilizing allowable ZMP (Zero-Moment-Point) region, which maxmizes the energy efficiency for cyclic gaits, based on three-dimensional LIPM (Linear Inverted Pendulum Model) for biped robots. As observed in natural human walking, variable ZMP manipulation is suggested, in which ZMP moves within the allowable region to reduce the joint stress (i.e., rapid acceleration and deceleration of body), and hence to reduce the consumed energy. In addition, opimization of footstep planning is conducted to decide the optimal step-length and body height for a given forward mean velocity to minimize a suitable energy performance - amount of energy required to carry a unit weight a unit distance. In this planning, in order to ensure physically realizable walking trajectory, we also considered geometrical constraints, ZMP stability condition, friction constraint, and yawing moment constraint. Simulations are performed with a 12-DOF 3D biped robot model to verify the effectiveness of the proposed method.

• 디자인학연구
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• 제19권2호
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• pp.355-364
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• 2006

애니메이션에서 등장하는 캐릭터들은 다양한 외형적인 모습과 성격들을 소유하고 있다. 이러한 개성과 성격들은 일반적으로 형태, 행동, 대화, 걷기 동작 등과 같은 다양한 요소들에 의해 표현된다. 특히, 걷기 동작은 캐릭터의 움직임 표현에 있어 가장 기본적인 요소이면서 캐릭터의 개성표현에 중요한 부분을 차지한다. 본 연구에서는 캐릭터의 특징이 잘 표현된 애니메이션들을 중심으로 음양오행이론을 접목하여 외형적 모습과 성격에 따라 캐릭터들을 분류한다. 그리고 분류한 캐릭터들의 동작을 분석함으로써 캐릭터의 개성과 움직임간의 관계를 제시한다.

• 한국운동역학회지
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• 제31권1호
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• pp.30-36
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• 2021

Objective: The objective of the present study was to analyze the relationship between strength of the lower extremity's joints and their local dynamic stability (LDS) of gait in elderly women. Method: Forty-five elderly women participated in this study. Average age, height, mass, and preference walking speed were 73.5±3.7 years, 153.8±4.8 cm, 56.7±6.4 kg, and 1.2±0.1 m/s, respectively. They were tested torque peak of the knee and ankle joints with a Human Norm and while they were walking on a treadmill at their preference speed for a long while, kinematic data were obtained using six 3-D motion capture cameras. LDS of the lower extremity's joints were calculated in maximum Lyapunov Exponent (LyE). Correlation coefficients between torque of the joints and LyE were obtained using Spearman rank. Level of significance was set at p<.05. Results: Knee flexion torque and its LDS was negatively associated with adduction-abduction and flexion-extension movement (p<.05). In addition, ratio of the knee flexion torque to extension and LDS was negatively related to internal-external rotation. Conclusion: In conclusion, knee flexion strength should preferentially be strengthened to increase LDS of the lower extremity's joints for preventing from small perturbations during walking in elderly women.

• 한국정밀공학회지
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• 제31권12호
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• pp.1141-1146
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• 2014

As life expectancy becomes longer, reduction of human muscular strength threatens quality of human life. Many robotic devices have thus been developed to support and help human daily life. This paper deals with a new type of in-wheel actuator that can be effectively used for the robotic devices. BLDC motor, drive board, brake, ARS (Attribute Reference System), and torque sensor are combined in the single actuator module. The torque sensor is used to recognize human intention and the in-wheel actuator drives walking aids in our system. Its feasibility was tested with the active walking aid device equipped with the in-wheel actuator. Based on it, we designed an admittance filter algorithm to react on uphill and downhill drive. By adjusting mass, damping, and spring parameters in accordance with the ARS output, it provided convenient drive to the old on uphill and downhill walks.

• 전자공학회논문지SC
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• 제49권1호
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• pp.20-28
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• 2012

보행을 관찰하고 객관적인 정보를 추출하여 그 기능을 평가하는 것을 보행 분석이라고 한다. 최근 사용되는 보행 측정 장비들은 다수의 카메라, 지면 반력 측정 장치로 구성되어 고가이며, 이를 설치할 넓은 장소를 필요로 한다는 단점이 있다. 본 연구에서는 이러한 문제점을 해결하기 위해 단일 카메라를 통해 얻은 영상에서 마커 없이 인체의 3차원 보행 동작을 측정하는 기법을 제안한다. 파티클 필터를 사용하여 훈련 데이터와 보행에 관한 사전 정보 없이 사람의 동작을 추적한다. 인체와 지면에 관한 동역학을 통해 물리적으로 합당한 인체의 동작들을 생성하였다. 보행 영상에서 계산한 모든 관절의 평균 에러는 제안한 방법에서 $12.4^{\circ}$로, 기존 파티클 필터의 에러 $34.6^{\circ}$보다 작았다. 이러한 결과를 바탕으로 단일 카메라만으로 보행을 정량적으로 측정하여 기존 복잡한 장비를 대체할 수 있는 가능성을 제시하였다.